var page = 1;


function loadXMLDoc(){
    var xmlhttp;
    if(window.XMLHttpRequest){
        xmlhttp = new XMLHttpRequest();
    }else{
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
    }
    xmlhttp.onreadystatechange = function(){
        if(xmlhttp.readyState == 4 && xmlhttp.status == 200){
            var json = JSON.parse(xmlhttp.responseText);
            for(let i = 0;i<json.shop.length;i++){
                console.log(json.shop[i])
                var img = document.createElement('img');
                img.src = json.shop[i].pic;
                var h3 = document.createElement('h3');
                h3.innerHTML = json.shop[i].title;
                var p = document.createElement('p');
                p.innerHTML = json.shop[i].desc;
                var p2 = document.createElement('p');
                p2.innerHTML = "￥";
                var span = document.createElement('span');
                span.innerHTML = json.shop[i].price;
                p2.appendChild(span);
                var div = document.createElement('div');
                div.appendChild(img);
                div.appendChild(h3);
                div.appendChild(p);
                div.appendChild(p2);
                console.log(div);
                document.querySelector("#list").appendChild(div)
            }
        }
    }
    xmlhttp.open("GET",page + ".json",true);
    xmlhttp.send();
}
loadXMLDoc()


document.querySelector("#btn").addEventListener('click',function(){
    if(page >4){
        page = 1;
    }else{
        page++;
    }
    document.querySelector("#list").innerHTML = '';
    loadXMLDoc();
})